Commensal Microbiota and Cancer Immunotherapy: Harnessing Commensal Bacteria for Cancer Therapy

Prioritizing gut microbial SNPs linked to immunotherapy outcomes in NSCLC patients by integrative bioinformatics analysis

BACKGROUND

The human gut microbiome has emerged as a potential modulator of treatment efficacy for different cancers, including non-small cell lung cancer (NSCLC) patients undergoing immune checkpoint inhibitor (ICI) therapy. In this study, we investigated the association of gut microbial variations with response against ICIs by analyzing the gut metagenomes of NSCLC patients.

METHODS

Strain identification from the publicly available metagenomes of 87 NSCLC patients, treated with nivolumab and collected at three different timepoints (T0, T1, and T2), was performed using StrainPhlAn3. Variant calling and annotations were performed using Snippy and associations between microbial genes and genomic variations with treatment responses were evaluated using MaAsLin2. Supervised machine learning models were developed to prioritize single nucleotide polymorphisms (SNPs) predictive of treatment response. Structural bioinformatics approaches were employed using MUpro, I-Mutant 2.0, CASTp and PyMOL to access the functional impact of prioritized SNPs on protein stability and active site interactions.

RESULTS

Our findings revealed the presence of strains for several microbial species (e.g., Lachnospira eligens) exclusively in Responders (R) or Non-responders (NR) (e.g., Parabacteroides distasonis). Variant calling and annotations for the identified strains from R and NR patients highlighted variations in genes (e.g., ftsA, lpdA, and nadB) that were significantly associated with the NR status of patients. Among the developed models, Logistic Regression performed best (accuracy > 90% and AUC ROC > 95%) in prioritizing SNPs in genes that could distinguish R and NR at T0. These SNPs included Ala168Val (lpdA) in Phocaeicola dorei and Tyr233His (lpdA), Leu330Ser (lpdA), and His233Arg (obgE) in Parabacteroides distasonis. Lastly, structural analyses of these prioritized variants in objE and lpdA revealed their involvement in the substrate binding site and an overall reduction in protein stability. This suggests that these variations might likely disrupt substrate interactions and compromise protein stability, thereby impairing normal protein functionality.

CONCLUSION

The integration of metagenomics, machine learning, and structural bioinformatics provides a robust framework for understanding the association between gut microbial variations and treatment response, paving the way for personalized therapies for NSCLC in the future. These findings emphasize the potential clinical implications of microbiome-based biomarkers in guiding patient-specific treatment strategies and improving immunotherapy outcomes.

Physiological markers for immunotherapeutics: a review

Immunotherapy has been advanced through multiple approaches, including immunogenic cytokines, monoclonal antibodies, therapeutic vaccinations, adoptive cell transfer, stem cell transplantation, and oncolytic viruses. This review analyses various strategies in genomics, transcriptomics, single-cell techniques, computational analysis, big data, and imaging technologies for the identification of tumour microbiota and microenvironments. Immunotherapy is becoming acknowledged as a feasible cancer treatment method, facilitating innovative cancer medicines and personalized medicine techniques.

Cephalomannine reduces radiotherapy resistance in non-small cell lung cancer cells by blocking the β-catenin-BMP2 signaling pathway

BACKGROUND

The management of non-small cell lung cancer (NSCLC) often includes the use of radiotherapy, with individual outcomes being impacted by the tumor's response to this treatment modality. Cephalomannine (CPM), a taxane diterpenoid found in Taxus spp, has been found to have anti-tumor activity. This study was aim to the explore the role and mechanism by which CPM affects radiotherapy resistance in NSCLC.

METHODS

H460 cells were pretreated with different doses of CPM. H460 cells were transfected with β-catenin overexpression plasmids. The cell viability, colony-forming ability, migration ability, and sphere-forming ability and apoptosis of the cells were measured by using CCK-8, colony-forming, transwell, and sphere-forming assay and flow cytometry. Western blot assay was employed to detect the expression of β-catenin and BMP2.

RESULTS

The cell viability, proliferation, migration and sphere-forming ability of cells in the radiotherapy-resistant (RR) group were significantly higher than those in the radiotherapy-sensitivity (RS) group. Conversely, the apoptosis rate of cells in the RR group was lower than that in the RS group. However, after CPM pretreatment of RR group cells, the above phenomena were reversed in a CPM dose-dependent manner. Subsequently, pretreatment with CPM resulted in a decrease in the expression levels of β-catenin and BMP2 in the RR group. In addition, overexpression of β-catenin mitigated the inhibitory effects of CPM on radiotherapy-resistant NSCLC cells.

CONCLUSION

CPM has the potential to decrease radiotherapy resistance in NSCLC cells by inhibiting the β-catenin-BMP2 signaling pathway, promoting apoptosis, and ultimately impeding cell growth.

Cancer therapy with the viral and bacterial pathogens: The past enemies can be considered the present allies

Cancer continues to be one of the leading causes of mortality worldwide despite significant advancements in cancer treatment. Many difficulties have arisen as a result of the detrimental consequences of chemotherapy and radiotherapy as a common cancer therapy, such as drug inability to penetrate deep tumor tissue, and also the drug resistance in tumor cells continues to be a major concern. These obstacles have increased the need for the development of new techniques that are more selective and effective against cancer cells. Bacterial-based therapies and the use of oncolytic viruses can suppress cancer in comparison to other cancer medications. The tumor microenvironment is susceptible to bacterial accumulation and proliferation, which can trigger immune responses against the tumor. Oncolytic viruses (OVs) have also gained considerable attention in recent years because of their potential capability to selectively target and induce apoptosis in cancer cells. This review aims to provide a comprehensive summary of the latest literature on the role of bacteria and viruses in cancer treatment, discusses the limitations and challenges, outlines various strategies, summarizes recent preclinical and clinical trials, and emphasizes the importance of optimizing current strategies for better clinical outcomes.

Microbiome and cancer: from mechanistic implications in disease progression and treatment to development of novel antitumoral strategies

Cancer is a very aggressive disease and one of mankind's most important health problems, causing numerous deaths each year. Its etiology is complex, including genetic, gender-related, infectious diseases, dysbiosis, immunological imbalances, lifestyle, including dietary factors, pollution etc. Cancer patients also become immunosuppressed, frequently as side effects of chemotherapy and radiotherapy, and prone to infections, which further promote the proliferation of tumor cells. In recent decades, the role and importance of the microbiota in cancer has become a hot spot in human biology research, bringing together oncology and human microbiology. In addition to their roles in the etiology of different cancers, microorganisms interact with tumor cells and may be involved in modulating their response to treatment and in the toxicity of anti-tumor therapies. In this review, we present an update on the roles of microbiota in cancer with a focus on interference with anticancer treatments and anticancer potential.

Cold exposure, gut microbiota and health implications: A narrative review

Temperature has been recognized as an important environmental factor affecting the composition and function of gut microbiota (GM). Although research on high-temperature impacts has been well studied, knowledge about the effect of cold exposure on GM remains limited. This narrative review aims to synthesize the latest scientific findings on the impact of cold exposure on mammalian GM, and its potential health implications. Chronic cold exposure could disrupt the α-diversity and the composition of GM in both experimental animals and wild-living hosts. Meanwhile, cold exposure could impact gut microbial metabolites, such as short-chain fatty acids. We also discussed plausible biological pathways and mechanisms by which cold-induced changes may impact host health, including metabolic homeostasis, fitness and thermogenesis, through the microbiota-gut-brain axis. Intriguingly, alterations in GM may provide a tool for favorably modulating the host response to the cold temperature. Finally, current challenges and future perspectives are discussed, emphasizing the need for translational research in humans. GM could be manipulated by utilizing nutritional strategies, such as probiotics and prebiotics, to deal with cold-related health issues and enhance well-being in populations living or working in cold environments.

Immunotherapy: Advancing glioblastoma treatment-A narrative review of scientific studies

BACKGROUND

Glioblastoma (GB) is an aggressive and deadly brain tumor with a poor prognosis despite the current standard of care, including surgery, radiation, and chemotherapy.

RECENT FINDINGS

In recent years, there has been increasing interest in the potential of immunotherapies, seen to be effective in treating other cancers, in the treatment of GB. This comprehensive review presents an in-depth analysis of the remarkable progress of immunotherapy in GB treatment, focusing on human clinical studies. It also analyzes the current findings, challenges, and limitations that underscore the transformative potential of immunotherapy in managing GB. Of particular significance, it delves into the intriguing interaction of the human microbiome with immunotherapy as a novel avenue for enhancing treatment outcomes of GB.

CONCLUSION

This study sheds light on the complex GB therapy landscape and the cutting-edge strategies that show promise for enhancing patient prognosis.

Bacteria-based immunotherapy for cancer: a systematic review of preclinical studies

Immunotherapy has been emerging as a powerful strategy for cancer management. Recently, accumulating evidence has demonstrated that bacteria-based immunotherapy including naive bacteria, bacterial components, and bacterial derivatives, can modulate immune response via various cellular and molecular pathways. The key mechanisms of bacterial antitumor immunity include inducing immune cells to kill tumor cells directly or reverse the immunosuppressive microenvironment. Currently, bacterial antigens synthesized as vaccine candidates by bioengineering technology are novel antitumor immunotherapy. Especially the combination therapy of bacterial vaccine with conventional therapies may further achieve enhanced therapeutic benefits against cancers. However, the clinical translation of bacteria-based immunotherapy is limited for biosafety concerns and non-uniform production standards. In this review, we aim to summarize immunotherapy strategies based on advanced bacterial therapeutics and discuss their potential for cancer management, we will also propose approaches for optimizing bacteria-based immunotherapy for facilitating clinical translation.

The long and winding road of faecal microbiota transplants to targeted intervention for improvement of immune checkpoint inhibition therapy

INTRODUCTION

Immune checkpoint inhibition (ICI) therapy has revolutionized the treatment of cancer. Inhibitory molecules, either on the tumor or on cells of the immune system, are blocked, allowing the immune system of the patient to attack and eradicate the tumor. Not all patients respond to ICI therapy, and response or non-response has been associated with composition of gut microbiota.

AREA COVERED

Fecal microbiota transplantation (FMT) is used as adjunctive therapy in order to improve the outcome of ICI. ClinicalTrials.gov, and other databases were searched (October 2022) for studies dealing with gut microbiota modification and the outcome of ICI.

EXPERT OPINION

There is ample evidence for the beneficial effect of FMT on the outcome of ICI therapy for cancer, especially melanoma. Progress is being made in the unraveling of the mechanisms by which microbiota and their metabolites (butyrate and the tryptophan metabolite indole-3-aldehyde) interact with the mucosal immune system of the host. A better understanding of the mechanisms involved will allow the identification of key bacterial species which mediate the effect of FMT. Promising species are Faecalibacterium prausnitzii, Eubacterium rectale, Bifidobacterium adolescentis, B. bifidum, and B. longum, because they are important direct and indirect butyrate producers.

Microbial Components and Effector Molecules in T Helper Cell Differentiation and Function

The mammalian intestines harbor trillions of commensal microorganisms composed of thousands of species that are collectively called gut microbiota. Among the microbiota, bacteria are the predominant microorganism, with viruses, protozoa, and fungi (mycobiota) making up a relatively smaller population. The microbial communities play fundamental roles in the maturation and orchestration of the immune landscape in health and disease. Primarily, the gut microbiota modulates the immune system to maintain homeostasis and plays a crucial role in regulating the pathogenesis and pathophysiology of inflammatory, neuronal, and metabolic disorders. The microbiota modulates the host immune system through direct interactions with immune cells or indirect mechanisms such as producing short-chain acids and diverse metabolites. Numerous researchers have put extensive efforts into investigating the role of microbes in immune regulation, discovering novel immunomodulatory microbial species, identifying key effector molecules, and demonstrating how microbes and their key effector molecules mechanistically impact the host immune system. Consequently, recent studies suggest that several microbial species and their immunomodulatory molecules have therapeutic applicability in preclinical settings of multiple disorders. Nonetheless, it is still unclear why and how a handful of microorganisms and their key molecules affect the host immunity in diverse diseases. This review mainly discusses the role of microbes and their metabolites in T helper cell differentiation, immunomodulatory function, and their modes of action.

A Chinese herbs complex ameliorates gut microbiota dysbiosis induced by intermittent cold exposure in female rats

Cold is a common source of stress in the alpine areas of northern China. It affects the microbial community, resulting in the invasion of pathogenic microorganisms and intestinal diseases. In recent years, studies have reported that Chinese herbal extracts and their fermentation broth have a significant beneficial effect on gut microbiota. This study aimed to investigate the probiotic effect of a self-designed Chinese herbs complex on the gut microbiota of rats exposed to cold. The rats were treated with intermittent cold exposure and Chinese herbs complex for 14 days, and the gut microbiota composition and other parameters were assayed. The 16s ribosomal DNA high-throughput sequencing and analysis confirmed that the Chinese herbs complex positively improved the gut microbiota. We found that cold exposure could lead to significant changes in the composition of gut microbiota, and affect the intestinal barrier and other physiological functions. The relative abundance of some probiotics in the genus such as Roseburia, Parasutterella, and Elusimicrobium in rats treated with Chinese herbs complex was significantly increased. Serum D-lactic acid (D-LA) and lipopolysaccharide (LPS) were increased in the cold exposure group and decreased in the Chinese herbs complex-treated group. Moreover, the Chinese herbs complex significantly increased the protein expression of occludin. In conclusion, the Chinese herbs complex is effective in restoring the gut microbiota caused by cold exposure, improving the function of the intestinal barrier, and may act as a prebiotic in combatting gut dysbiosis.

Emerging role of human microbiome in cancer development and response to therapy: special focus on intestinal microflora

In recent years, there has been a greater emphasis on the impact of microbial populations inhabiting the gastrointestinal tract on human health and disease. According to the involvement of microbiota in modulating physiological processes (such as immune system development, vitamins synthesis, pathogen displacement, and nutrient uptake), any alteration in its composition and diversity (i.e., dysbiosis) has been linked to a variety of pathologies, including cancer. In this bidirectional relationship, colonization with various bacterial species is correlated with a reduced or elevated risk of certain cancers. Notably, the gut microflora could potentially play a direct or indirect role in tumor initiation and progression by inducing chronic inflammation and producing toxins and metabolites. Therefore, identifying the bacterial species involved and their mechanism of action could be beneficial in preventing the onset of tumors or controlling their advancement. Likewise, the microbial community affects anti-cancer approaches’ therapeutic potential and adverse effects (such as immunotherapy and chemotherapy). Hence, their efficiency should be evaluated in the context of the microbiome, underlining the importance of personalized medicine. In this review, we summarized the evidence revealing the microbiota's involvement in cancer and its mechanism. We also delineated how microbiota could predict colon carcinoma development or response to current treatments to improve clinical outcomes.